The present invention proposes providing a dirigible balloon with a flexible-walled enclosure containing helium that supports the balloon, together with means for modifying the volume of the flexible enclosure.
The present invention can be applied to any type of variable-lift device making use of an enclosure containing helium. Helium can be replaced by any other gas that is lighter than air, such as methane, ethane, hydrogen, or neon, for example.
Volume variation must take place without friction against the rigid outer enclosure of the dirigible which defines its aerodynamic shape, while nevertheless enabling lift to be varied and enabling varying forces to be transmitted depending on the flight altitude required of the apparatus. Landing, take-off, and varying altitude are then all performed very easily using the novel device described in the present invention.
When the flexible-walled enclosure is fully deployed, its shape is substantially cylindrical. When the means enabling the volume of the enclosure to be modified are operated, the flexible wall can take on a folded shape that lies within its initial substantially cylindrical shape.
The present invention is defined in general terms by a variable-lift device comprising a structure an internal enclosure containing a lighter than air gas, e.g. helium, carrying said structure. The device is characterized by the fact that the internal enclosure has a flexible wall and in that the device has means for modifying the volume of the internal enclosure.
The means for modifying the volume of the internal enclosure may comprise at least one cable connecting the flexible wall to at least one winch. Said cable may be connected to the flexible wall by means of at least one pulley. Said pulley may be fixed to at least one beam fixed on the flexible wall.
In a particular embodiment of the invention, the internal enclosure is provided near its bottom with a set of pulleys and near its top with two beams provided with another set of pulleys so as to co-operate with said cable to constitute block-and-tackle.
In a particular embodiment of the invention, the means for modifying the volume of the internal enclosure may be located inside the internal enclosure.
The structure of the device of the invention may include a ballast tank comprising at least one supply of helium communicating with the internal enclosure via at least one valve and at least one compressor. The ballast tank may comprise two symmetrical tanks.
The structure of the device of the invention may comprise an external enclosure containing the internal enclosure. The volume between the internal enclosure and the external enclosure may communicate with the outside of the dirigible balloon through at least one orifice provided with at least one heat exchanger. A heat exchanger may use as its heat source the exhaust gases from an engine. A heat exchanger may use as its heat sink the water that results from condensation phenomena.
The device of the invention may be used in a dirigible balloon for hoisting or transporting loads.